/Engine/Source/Runtime/SignalProcessing/Public/SampleBuffer.h
InIndex [0.0f, NumSamples - 1.0f] OutFrame is the multichannel output for one index value Returns InIndex wrapped between 0.0 and NumFrames
float GetAudioFrameAtFractionalIndex ( float InIndex, [TArray](API\Runtime\Core\Containers\TArray)< SampleType > & OutFrame ) const